The Origin Of Free Exciton-Like Emission In Znsete Alloy

Photoluminescence (PL) spectra of ZnSeTe alloy system with low Te concentration shows quite strong emission bands in green-blue range at low temperatures. A free exciton (FE)-like peak appears additionally to the blue band. In detailed measurements of the temperature dependence of PL profile, it is revealed that the FE-like emission consists of a double peak at low temperatures. The energy difference between the peaks corresponds to that between (A(0), x) and (D-0, x) of the mother crystal, ZnSe. The FE-like peak survives even at the room temperature as a broad structure. The FE-like emission peak of the ZnSe:Te alloy is due to the excitonic band edge emission, I-2: Te.